He was born a girl by the name of Melissa, but it was a name that never fit. And all his life, more than anything, Mel, as he now calls himself, has wanted to fit.

Mel Rutherford is a married father of five-year-old twin boys and stepfather to a 17-year-old girl. One of Canada’s leading experts in autism, the 41-year-old is an associate professor of psychology and director of the Human Development Centre at McMaster University in Hamilton, Ont. He is a graduate of Yale, the winner of a Fulbright Fellowship and holds a Canada Research Chair.

Rutherford is also transgendered - a “trans man” or FTM (female to male) who, over the past two years, has made a successful transition to living life fully as a man. His body has been transformed by weekly testosterone injections - he has a thicker neck, narrower hips, a receding hairline, a beard and, yes, a higher sex drive. His voice has dropped several octaves.

He’s said goodbye to the monthly mess of tampons and pads and hello to the daily practice of shaving, a ritual he relishes. Most significantly, he and everyone in his world has made the pronoun switch from “she” to “he.”

Beyond the physical transformation, there’s been an even more profound shift. No longer is there sexual ambiguity about Rutherford’s gender, no confusion about whether he’s a masculine-looking female or a feminine-looking male. The question of androgyny has been replaced by the certainty of his sex. Gone is the former wariness he used to experience when meeting people for the first time.

“I was often misperceived, and people had a hard time categorizing me and figuring out what box I fit into. That made for a lot of very awkward interactions,” says Rutherford. “Being more comfortable with others and feeling their acceptance is huge for me. The result has been a different relationship with the world.” For the first time in his adult life he can pass as a man with no hint of the woman he once was.

What’s remarkable about Rutherford’s transition is how seamless it’s been, the only ripple an occasional pronoun slipup from a friend or colleague. The smoothness of his passage from female to male is significant for what it says about our greater acceptance of trans culture.